No problems with the holes in the headstock. I put these on a "generic" Flying V. Was tight at first getting them in there. But not nearly enough where I had to drill. Just needed a little "massaging" So a good fit.

Only issue that I see may is that the screw hole on the side is in a slightly different spot than the previous tuners.

Did not fix all of my tuning issues, but still an improvement. Much better than the "cheapies" I used to have on this. Next, is to replace the nut.

These came standard on my Gibson Firebird and they are awesome tuners. Regardless of string type or tuning they hold and are very easily adjusted in small increments of tone. My guitar sat for over a month while I was on vacation and when i returned it was still in perfect tune.

I got these to replace the tuners on my SG Special Faded when I began running into tuning problems with the "green key" tuners that came stock on it. These were a fantastic improvement. Standard Grover quality. You can hardly go wrong with these.

New Grovers are OK, but no where as good as older, made in the US versions. I found the keys or buttons to be very poorly fitted to the shaft, allowing some play. This is very annoying when you try to fine tune. But, they're adequate and reasonably priced.